15 December 2009

I’ve got a lovely bunch of coconuts’ shells

Octopuses using coconut shells has been all over the web the last couple of days due to the publication today of a new paper by Finn and colleagues. The title is helping generate the attention: tool use.

This is a cool finding, but it is not as path-breaking as one might think.

Second, this is not the first time the phrase “tool use” has been used regarding octopus behaviour. I remember having discussions about tool use in octopuses arising from discussions with Jennifer Mather, my undergrad supervisor. In her field site, she noted that octopuses made dens. These were not just nooks and crannies that octopuses crawled into. The octopuses actively modified their dens by bringing in rocks to block the entrance.

So we’ve known for 15 years that octopuses can actively use objects in their environment for protective purposes. I think the coconut shell carrying and use could be an extension of the den modifying behaviour. The difference with coconuts is that the octopuses can move them around with them, and it’s hard to think of rocks an octopus could do that to.

The coconut carrying behaviour is interesting not because it shows tool use as such, but because it shows anticipation and planning. They show octopuses carrying the coconut shells under their bodies. Finn and company argue that is costly behaviour, except that the octopus could then cover itself with the two halves of the coconut.

In reading the paper, though, I am not sure if they saw a case where an octopus carrying the coconut shells switched to covering itself with the coconut shell. Yes, I’m being picky with that criticism. They may have seen that behaviour. Even if they did not see it, it’s a completely reasonable assumption that the octopuses do use the shells as shelter, and I have no other hypothesis as to what the octopuses are doing with those shells. But if they did not see it, it’s important to keep in mind that they’re inferring the connection between carrying the coconut shells and using them as shelter.

The link (thanks!) is the same as the “Supplemental video 1” that is published online with the paper. It has five continuous video segments spliced together.

1. Octopus excavating a shell from under sand.

2. Octopus peeking out from underneath shell.

3. Octopus excavating shell and walking away with it.

4. Octopus walking with shell and stopping.

5. Octopus pulling shells together.

Because of the cuts in the video, there’s no way to tell if the octopus in the last sequence is the same one seen in the previous sequences. It’s possible that the shells the octopus is using in sequence 5 were already there, rather than the octopus having brought the pieces along.

Great to find your post via Circus o/t Spineless. The video (apparently independent of the research) I used in my related post seems to show the behavior you are looking for: transportation then bivouacing; though with two scallops and coconut fragment and not across a far distance.

I'm visiting via Circus of the Spineless. As an anthropologist, trying to understand what humans are all about, I always love stories that show tool use in other species. Thanks for providing more information on this in octopus. Makes me eager to learn more.